1. Field of the Invention:
The invention relates to a power semiconductor module having a plastic housing, an electrically insulating substrate inserted in the lower surface of the plastic housing as a carrier for electrical components, a metallization disposed at least on the upper surface of the substrate, the metallization on the upper surface being patterned to form conductor tracks, and components such as semiconductor components and connecting elements soldered onto the patterned metallization. The invention also relates to a method for producing such a module.
2. Description of the Related Art:
Such a power semiconductor module is known from German Published, Non-Prosecuted Application DE-CS 36 04 313. The prior art power semiconductor module includes a plastic housing which is open at the bottom. A ceramic substrate which is used as the base surface has a patterned metallization on the upper surface thereof onto which the power semiconductor components and electrical connecting elements for internal module connections are soldered. In addition, connecting elements for external main terminals carrying load current are welded to the metallization of the substrate. The control terminals are so-called outlier terminals or terminals with a projecting tip because the projections thereof on the plane of the substrate lies outside the substrate area. The control terminals are soldered on in a second soldering step or inserted in tin bushings after wire connections have been produced with wire bonders. However, the connecting lugs for the main connections are soldered vertically onto the substrate in a standing position in the first soldering step, just as is the case in other conventional modules. In order to do this, an expensive welding jig or form is necessary in order to locate the connecting lugs in the required position during the soldering operation and to prevent them from tipping over.
Page 156 and FIG. 4e of the publication Electronic Design of Jan. 8, 1987 discloses a module producing process in which the connecting elements are soldered on in a recumbent or lying position. As a result of this on one hand, access is still made possible for a bonding tool after soldering and in addition, a soldering jig becomes unnecessary or at least only a simple alignment device is required. However, the connecting lugs have to be separated from a frame structure after soldering and bent upwards. This is a certain complication and may mechanically stress the solder joints.